1. Field of the Invention
The invention relates to an image sensor module, and in particular to an injection molded image sensor module capable of receiving optical signals more precisely.
2. Description of the Related Art
Referring to FIG. 1, a conventional image sensor module includes a lens holder 10, a lens barrel 20, and an image sensor 30. The lens holder 10 has a top face 12, a bottom face 14 and a hole 16 penetrating through the lens holder 10 from the top face 12 to the bottom face 14. An internal thread 18 is formed on an inner wall of the hole 16 of the lens holder 10. The lens barrel 20 formed with an external thread 22 is inserted from the top face 12 of the lens holder 10, received within the hole 16, and screwed to the internal thread 18 of the lens holder 10. The lens barrel 20 is formed with a transparent region 24 under which an aspheric lens 26 and an infrared filter 28 are arranged in sequence. The image sensor 30 has a first surface 32 and a second surface 34 opposite to the first surface 32 on which a transparent layer 36 is arranged. The image sensor 30 is bonded to the bottom face 14 of the lens holder 10 through the transparent layer 36. The screwed length between the lens barrel 20 and the lens holder 10 may be adjusted to control the distance from the aspheric lens 26 of the lens barrel 20 to the transparent layer 36 of the image sensor 30.
However, if the transparent layer 36 of the image sensor 30 is not precisely positioned within the hole 16 of the lens holder 10, the received optical signals may be shifted.